1. Field of the Invention
This invention relates to door structures.
2. Background of the Prior Art
A known door structure includes:
a first plate serving as fixed frame with an opening enclosed by a peripheral edge; and
a door connected pivotally to this first plate by at least one hinge construction such that with its peripheral zone the door can co-act sealingly with said peripheral edge;
which first plate carries a number of peripherally arranged clamps, which clamps are simultaneously rotatable by a collective operating mechanism with an operating handle and through rotation can co-act with the peripheral zones of corresponding non-round continuous holes in the door, which peripheral zones have for each clamp a contact surface inclining relative to the main plane of the door structure in the closed situation, which continuous holes have a form such that a clamp can pass therethrough.
The known door structure is used for instance in explosion-sensitive conditions, such as for instance in the extraction of fossil fuel, as well as for military applications, for instance on board military vessels.